GB2099775A - A rotatable stock container unit - Google Patents

Abstract

A rotatable stock container unit for the storage of articles such as electronic parts, of the like. A plurality of container tiers are arranged vertically one above another, each tier comprising outer and inner rail means (2,3), guide channel means (4) arranged therebetween, an endless traction chain (20), a driving means (7 to 12) therefor, and a series of stock containers (16), releasably secured to the traction chain, moving on and along the rail means, so that any container may be reached most expeditiously by selectively operating each container conveying tier. Also described are means for adjusting the driving means and track length to compensate for wear in the traction chain. <IMAGE>

Description

SPECIFICATION A rotatable stock container unit The present invention relates to a rotatable stock container unit that includes a plurality of open containers for the storage of articles such as electronic parts, or the like, movably arranged in a plurality of container conveying tiers arranged vertically one above another.

The typical design of a conventional stock container unit of movable type including a plurality of movable open containers is such that each of the containers is carried by four freerunning wheels on and along a pair of outer and inner rails disposed parallel to each other, two wheels engaging each rail. With such construction, when the container runs along a curved section of the rail, it is observed that these wheels are forced to turn along the curvature of the rail, the outer wheels differing in their running direction and number of revolutions from the inner wheels, so causing wheels continuously to slip slightly sideways off their original running direction while passing through the curved section, thus resulting in wear of the wheels subjecting the container to a substantial resistance during running operation.

A further disadvantage of a stock container unit of the type mentioned above, is that after a long period of use the joints or connecting points of an endless traction chain connecting the containers will become worn so that the total length of the chain will increase, so affecting smooth running of the chain along the guide rails and eventually causing the containers to run out of their tracks.

To overcome this, it has been the practice to mount two shafts for the chain driving sprockets so that they are adjustable insofar as the distance between their axes is concerned, so that a possible slackness due to wear of the chain may adjustably be taken up. It is also known to provide the guide rails with split parts near their ends, either on a straight side or at junction points between straight and curved sections, the split parts being adjustable to extend the total length of the straight sections of the rails to an extent that would correspond to the distance required to compensate for the amount of slack on the driving chain. The gap or gaps formed between the split parts and the ends of the principal rail portions may be filled up with a filler plate or plates so as to form a smooth continuation of the rails where so connected.For this purpose there has been required a variety of filler plates having many different sizes, enough to cover such gaps as may be formed from the axial adjustment of the sprocket shaft or shafts. Fitting of such filler plates means a trouble-some job involving substantial time and labour.

According to the present invention a rotatable stock container unit includes a plurality of container conveying tiers arranged vertically one above another, each tier comprising: (a) an endless loop of outer rail means extending in a horizontal plane; (b) inner rail means extending in a horizontal plane, arranged inside the outer rail means at a certain distance away therefrom; (c) guide channel means extending in a horizontal plane, arranged between the inner end and the outer rail means at a certain distance away therefrom; (d) an endless traction chain loop which is guided by the guide channel means and is adapted to be moved along the same; (e) means for driving the traction chain; and (f) a plurality of containers releasably secured to the traction chain means so as to be moved on and along the inner and outer rail means together with the traction chain.

Preferably, each outer rail means is of generally eiliptical shape and comprises a pair of discrete straight sections extending parallel to each other and a pair of discrete curvilinear sections each connecting adjacent free ends of the straight sections, and the length of the outer rail means is adjustable so as to compensate for slackness in the traction chain by a coupling plate which is slidably and closely fitted into a gap adjustably formed between the discrete straight section and the discrete curvilinear section of the outer rail means so as to form a part of the outer rail.

The invention will become more apparent from the following detailed description of preferred embodiments thereof, with reference to the accompanying drawings, in which: Fig. 1 is a front elevation view showing, partly broken away, a first embodiment of a rotatable stock container unit according to the present invention; Fig. 2 is an enlarged fragmentary plan view showing the main part of the unit of Fig. 1; Fig. 3 is a vertical cross-section taken along the line Ill-Ill in Fig. 2; Fig. 4 is an enlarged view showing a container part of the container unit shown in Fig. 1; Fig. 5 is a vertical cross-section taken along the line V-V in Fig. 4; Fig. 6 is a view similar to Fig. 2 showing the main part of a unit according to a second embodiment of the invention;; Fig. 7 is a vertical cross-section taken along the line VIl-VIl in Fig. 6; Fig. 8 is a view similar to Fig. 4 showing the container part of the unit shown in Fig. 6; Fig. 9 is an enlarged plan view showing a mount plate; Fig. 10 is a view similar to Fig. 1 showing generally a container unit according to a third embodiment of the invention; Fig. 11 is a view similar to Fig. 2 showing the main part of the unit shown in Fig. 10; Fig. 12 is a vertical cross-section taken along the line Xll-XlI in Fig. 11; Fig. 1 3 is an enlarged front elevation showing detail of a split part of an outer rail; Fig. 14 is an enlarged plan view corresponding to Fig. 13; Fig. 1 5 is an enlarged fragmentary view showing, partly in section, a central upper part of the unit;; Fig. 1 6 is a cross-section taken along the line XVl-XVI in Fig. 15; and Fig. 1 7 is an enlarged fragmentary view showing a container used in the container unit of the invention.

Referring now to Fig. 1, there is shown a unit having a structure 1 of a generally rectangular parallelopiped shape constructed with a plurality of struts 1 a standing upright and equally spaced one from another, and a plurality of bridge beams 16 extending between adjacent struts 1 a at right angles therewith to connect the struts together.

There are provided a desired number of outer rails 2 surrounding the outer circumference of the frame structure 1, each outer rail being of generally elliptical shape and the rails being arranged vertically one above another at desired intervals. A corresponding number of pairs of straight inner rails 3 extend parallel to the straight sections of the outer rails 2, the inner rails also being arranged one above another at desired intervals, yet each inner rail being at a relatively higher level than the level of the corresponding outer rail. The inner rails are wholly straight, and are not joined at their ends by curved sections as are the outer rails.

Also, there are provided guide channels 4 each having a generally U-shaped transverse crosssectional shape, each channel lying between an associated pair of outer and inner rails 2, 3, and having a straight section extending parallel to, and at the same height as the straight section of the associated outer rail.

First and second vertical shafts 5 and 6 stand upright in the centers of the right and left side semi-circular sections of the frame structure 1, respectively, as generally shown in Fig. 1 . The first shaft 5 is provided with a plurality of first driving sprockets 7 mounted rotatably on the shaft, each driving sprocket being located at the same level as a respective one of the guide channels 4. Each sprocket has a diameter substantially equal to the transverse distance between opposite sections of the channel at opposite sides of the frame structure, and has a plurality of depressions 7a spaced equally around the circumference thereof.

The first shaft 5 is provided with sets of first and second transmission sprockets 8 and 9, one set associated with each driving sprocket 7 and mounted coaxially with, and respectively above and below the associated driving sprocket and rotatable together therewith. With this construction, each driving sprocket 7 may be rotated together with its own pair of sprockets 8 and 9 by an independent prime mover, independently from any other driving sprocket 7 and its associated pair of sprockets 8 and 9.

A plurality of electric motors 10 are mounted on the right side of the frame structure as viewed in Fig. 1. Each motor has its driving sprocket 11 parallel to the shaft 5, and such sprocket is operatively connected to a respective one of the sprockets 9 by way of a respective endless drive chain 12, whereby each sprocket 9 and hence each of the first driving sprockets 7 and transmission sprockets 8 which belong to the same set may freely be rotated by the associated electric motor 10, independently from the other sets of sprockets 7, 8 and 9. Each motor can be operated independentlv from the others.

The second shaft 6 is provided with a plurality of second driving sprockets 14 and a plurality of second transmission sprockets 14, similar to the first driving sprockets 7 and the first transmission sprockets 8, respectively. The transmission sprockets 8 and 14 forming a corresponding pair are operatively connected with each other by way of an interlocking or driving chain 15; thus both first and second driving sprockets 7 and 13 forming a corresponding pair are rotated at an equal speed and in the same direction by the electronic motor 10 associated with that pair.

The apparatus includes a plurality of containers 1 6 of generally rectangular parallelopiped shape for storing required articles, each of its containers being mounted releasably upon a rectangular mount plate 1 7 by way of channeled cross members 1 7a which are disposed parallel to the two shorter sides of the mount plate.Each mount plate has two wheels 18 disposed under the outer longitudinal side thereof (the right hand side in Fig. 5) and a panel 1 7b bent upright at the inner longitudinal side thereof and carrying another pair of wheels 1 9. With such construction of the mount plate 17, each container 1 6 may thus be carried on the outer rail 2 and the inner rail 3 through the mount plate 1 7 having its wheels 1 8 and 1 9 engaging rails 2 and 3 respectively.

An endless traction chain 20 comprises, as typically shown in Figs. 2 and 4, a plurality of elongated coupling elements or strips 21 pivotally connected end-to-end with each other by a plurality of vertical connecting pins 22 so as to form an endless articulated loop. Each connecting pin 22 carries a roller 23 which rotatably engages within the respective guide channel 4 and also closely engages in the depressions 7a and 1 3a formed in the circumferences of the respective first and second driving sprockets 7 and 13.

Each container 1 6 has mount plate 1 7 suitably connected to the traction chain 20 by an convenient means, so that the plurality of containers may operatively be connected to the chain at predetermined intervals with each other.

With such construction of stock container unit, in operation, when the chosen motor 10 is operated, the first driving sprocket 7 operatively connected with this motor is rotated together with the second driving sprocket 13 corresponding thereto, thus causing the endless traction chain 20 running between these two sprockets to move along the guide channels 4.

Hence, the plurality of containers 1 6 connected to this particular traction chain 20 are driven in such a manner that at the straight section of the frame structure 1, the containers upon the mount plate 1 7 travel in straight line motion on and along the outer and inner rails 2 and 3, and at the curved or semi-circular track section where there is no inner rail 3, they are carried in curvilinear motion on the first or second driving sprockets 7 or 1 3 with their inner edges being supported generally on the circumferential areas of the sprockets, and the wheels 1 8 engaging the curved section of the outer rail 2.

Therefore, an operator may reach a desired article stocked in a certain container 16, by controlling automatically the positioning of this particular container to a predetermined place of handling through a shortest possible travel by using an electronic unit, not shown, to select a desired electric motor to be operated and to control the direction of rotation of that motor. The desired article may be manually removed from the container or may be reached by removing the whole container 1 6 from the mount plate 17.

When it is necessary to stock articles in order, the operator may operate the system in the reverse order.

In the embodiment as described above the interlocking chain 1 5 may be omitted and the second driving sprocket 13 may be a follower or driven sprocket, under drive from sprocket 7 through the traction chain 20. The outer rail 2 may be made in other closed loop forms, for example, in the form of a circle, with the inner rail 3 and the guide channel 4 arranged in like circular forms and disposed coaxially with respect to the outer rail 2. In this case it is also feasible to omit completely the second driving sprocket, the inner rail 3 and the guide channel 4 being of continuous semi-circular form coaxial with the outer rail.

As the stock container unit described is equipped with a large number of containers 1 6, a large variety of articles may be stocked in order in the manner that they may be reached expeditiously whenever so desired. In addition, since every container may readily be reached for loading and unloading operations with only one side of the unit left open for acces while leaving other sides blocked by adjacent furniture or the like, it may usefully be installed in the limited space of a building.

Also, as the tiers of containers of this unit may selectively be operated independently, it is possible simultaneously to operate more than one tier of containers to speed retrieval of articles as desired. This feature can contribute to an improvement in productivity on a production line in, for example, the electronic industry, where a variety of parts are required in the assembly work.

A second. embodiment of unit according to the invention is shown in Figs. 6 to 9. In this embodiment a single wheel 1 8a is provided in the centre of the outer longitudinal side of the mount plate 17, as best shown in Fig. 9, with all the remaining parts being identical to those described in the first mentioned embodiments of the invention, and indicated by identical reference numbers. In the first mentioned embodiment, due to the construction such that the two outer wheels 1 8 rigidly disposed near the outer corners of the mount plate 17 are designed to run on and along the outer rail 2, when a container 16 is pulled along the semi-circular track of the outer rail these two wheels 1 8 may take different tracks off the path as shown by chain line in Fig. 9.

Consequently, these wheels, during curvilinear motion of the mount plate are forced continuously to slip slightly sideways off their running direction, thus resulting in the wheels becoming worn in a relatively short period of use and the container being subjected to a substantial resistance to movement. In the second embodiment of the invention, in contrast, there is a single outer wheel 1 8a disposed at the centre of the outer longitudinal side of the mount plate 17. The axis of rotation of this wheel is thus oriented constantly in the centripetal direction of curvature of the path of motion so that the plane of rotation of this single wheel 1 8a may constantly comply with its own path of motion, thus relieving the wheel from an undue load and affording a smooth travel of a container 1 6.

During the curvilinear motion of the container 16, the inner side of the mount plate 1 7 is carried upon the generally circumferential area of the driving sprocket 7 or 13 and the mount plate 17 is operatively connected to the traction chain 20, and consequently, the container 1 6 may be held from tilting.

This second embodiment has been described in the context of an outer rail 2 generally elliptical including both straight and curved sections as parts. In the case that the outer rail 2 is of an entirely circular shape, the containers 1 6 may well travel along the circular track with a single wheel provided in the place of the two wheels 19 as in the first mentioned embodiment, together with a suitable mount between a container 1 6 and a traction chain 20 providing a specific cooperative function to prevent the container from tilting.

Alternatively, suitable means may be disposed at both the front and rear ends of adjacent containers or container mount plates to aid contact therebetween, whereby a plurality of containers may be operated free from any trouble during travel around the circular shaped track.

A third embodiment of the invention will now be described with respect to Figs. 10 to 1 7.

Again, the general construction is basically similar to that of the first mentioned embodiment and corresponding reference numerals are used in the drawings.

The unit has a plurality of outer rails 2 having an L-shaped transverse cross-sectional shape, and each extending in an elliptical form around the outer circumference of the frame structure 1.

The plurality of outer rails 2 are mounted at predetermined intervals one above another, each having a straight section 30 and a semi-circular section 31, as partly shown in Fig. 11.

As best shown in Figs. 13 and 14, while the end of each of the straight sections 30 of the outer rails 2 is right-angled, the end of each of the semi-circular sections 31 thereof is formed with the horizontal leg 31a defining an acute angle with respect to the opposite edge to the upright leg 31 b, an elongated opening 32 being provided near the end of each upright leg 31 b. Also, under the end of the straight section 31 , there is rigidly connected one end of a horizontal joint plate 33, an angled element 33a being fixed securely to the other end of the joint plate 33. With this arrangement, the straight section 30 and the semi-circular section 31 are joined together by way of bolts 34 secured through the elongated opening 32 in the upright leg 31 b to the angled element 33a.

The is also provided a filler plate 35 having a generally right-angled triangle shape in plan and having an elongated opening 36 extending at right-angles to the outer rail when installed in position. This filler plate 35 is adapted to be placed like a wedge between a gap of a trapezoid like shape that is formed between the opposed ends of the straight section 30 and the semi circular section 31 of the outer rail 2, with the acute-angled side of the filler plate abutting snugly along the corresponding side of the horizontal leg 31 a. There is thus provided an adjustable, smooth continuation between the horizontal leg ends of the opposed sections 30 and 31 of the rail 2, the filler plate being set in position by using a bolt 38 secured through the elongated opening 36 to the joint plate 33.In this manner, adjustment to compensate for slackness of the worn traction chain 20 can be effected as will be described further later.

As in the first mentioned embodiment of the invention, there are provided the straight inner rails 3 extending parallel to the straight sections 30 of the outer rails 2, and also the guide channels 4 having a generally U-shaped crosssectional shape and extending at the same level as, and parallel to, the straight sections 30 of the outer rail 2 intermediate the two rails 2 and 3.

There are also provided first and second vertical shafts 39 and 40 standing upright in the centres of the opposite semi-circular sections of the outer rail 2 in the manner as stated below.

More particularly, in the right hand section of the frame structure 1 there are provided a pair of shaft mount sections or bars 41 for the first shaft 39 having channelled legs 41a (see Fig. 15) extending in parallel with each other in the upper centre part of the semi-circular section of the unit, as generally shown in Fig. 11. Each of the channelled legs 41 a has elongated openings 42 extending longitudinalry along the shaft mount bar 41 (see Fig. 16). A shaft mount plate 44 is fixed in position on the shaft mount bars by way of bolts 43 secured through the elongated openings 42. In the centre of the shaft mount plate 44, the first shaft 39 is rotatably held at its upper end, and is also held at its opposite end in like manner, not shown, in the lower part of the frame structure 1.Also, the second vertical shaft 40 is rotatably mounted at the left hand part of the frame structure 1 in like manner.

As in the first mentioned embodiment of the invention, the first and second shaft 39 and 40 are provided with the plurality of first and second driving sprockets 7 and 13, the plurality of first transmission sprockets 8 and sprockets 9 and second transmission sprockets 14, respectively.

The axial position of the first and/or second vertical shaft 39 and/or 40 may be adjusted to compensate for slackness of the traction chain 20 due to wear in the elongated coupling elements thereof, which wear would eventually result in lack of smooth operation of the containers. To make such adjustment the first shaft 30, for example, is first shifted axially outwardly, or to the right as viewed in Fig. 11, by unscrewing the bolts 43 and sliding the shaft mounted plate to an extent enough to take up the slack of the traction chain 20. Each of the electric motors 10 corresponding to each of the first transmission sprockets 8 on this particular first shaft are also moved outwardly, or alternatively, the endless chains 12 are shortened. Similar adjustment of the second vertical shaft 40 may likewise be made at the same time.

Next, the semi-circular section 31 of the outer rail 2 is shifted outwardly or to the right as viewed in Fig. 11 by unscrewing the bolts 34 in the joint parts between the straight sections 30 and the semi-circular section 31 and then sliding the semicircular section 31 outwardly along the elongated openings 39 provided in the upright leg 31 b of the outer rail 2, so to extend the length of the entire outer rail 2 correspondingly to the amount of axial shaft of the first shaft 39. At this moment, there are formed gaps 37 between the opposed ends of the straight sections and the semi-circular section 31 of the outer rail 2.These gaps 37 may now be filled up by unscrewing the bolts 38 and then sliding the filler plates 35 toward the gaps along the elongated openings 36 so as to form a smooth continuation across the gaps 37 between the opposed horizontal leg ends of the straight and semi-circular sections 30 and 31.

If the traction chains 20 are replaced with new ones that are shorter than those previously in use the adjustment may be made with such procedures as mentioned above in the reverse order.

It is very advantageous that axial adjustment of the sprocket shafts can now be conducted readily without the necessity to prepare a variety of filler plates of different dimensions to be used in compensating for traction chains slackness.

Although the present invention has been described with reference to preferred embodiments thereof, it will be apparent that various changes and modifications can be made by those skilled in the art without departing from the scope of the present invention.

Claims (11)

Claims

1. A rotatable stock container unit including a plurality of container conveying tiers arranged vertically one above another, each tier comprising: (a) an endless loop of outer rail means extending in a horizontal plane; (b) inner rail means extending in a horizontal plane, arranged inside the outer rail means at a certain distance away therefrom; (c) guide channel means extending in a horizontal plane, arranged between the inner and the outer rail means at a certain distance away therefrom; (d) an endless traction chain loop which is guided by the guide channel means and is adapted to be moved along the same; (e) means for driving the traction chain; and (f) a plurality of containers releasably secured to the traction chain means so as to be moved on and along the inner and the outer rail means together with the traction chain.

2. A unit as claimed in claim 1 ,wherein each container is secured to the traction chain through a container support plate which is provided with inner wheel means running on the inner rail means and outer wheel means running on the outer rail means.

3. A unit as claimed in claim 2, wherein the inner and the outer wheel means comprise two inner wheels and two outer wheels, respectively.

4. A unit as claimed in claim 2, wherein the inner and the outer wheel means comprises two inner wheels and one outer wheel, respectively.

5. A unit as claimed in any one of claims 1 to 4, wherein each outer rail means is of generally elliptical shape and comprises a pair of discrete straight sections extending parallel to each other and a pair of discrete curvilinear sections each connecting adjacent free ends of the straight sections.

6. A unit as claimed in claim 5 wherein the inner rail means comprises first and second straight rails, each located said certain distance from an associated straight section of the outer rail means and extending parallel thereto.

7. A unit as claimed in claim 5 or claim 6 wherein the guide channel means comprises first and second straight channel sections, each located between an associated straight rail of the inner rail means and the associated straight section of the outer rail means.

8. A unit as claimed in any one of claims 5 to 7 wherein the length of the outer rail means is adjustable so as to compensate for slackness in the traction chain by a coupling plate which is slidably and closely fitted into a gap adjustably formed between the discrete straight section and the discrete curvilinear section of the outer rail means so as to form a part of the outer rail.

9. A unit as claimed in claim 8 wherein the coupling plate bridging the gap between the discrete straight section and the discrete curvilinear section of the outer rail means is formed in a trapezoidal shape.

10. A unit as claimed in claim 8 wherein the coupling plate bridging the gap between the discrete straight section and the discrete curvilinear section of the outer rail means is formed in a triangular shape.

11. A unit as claimed in any one of claim 8 to 10 wherein two cdupling plates are provided, fitted into gaps between respective ones of the discrete straight sections and the discrete curvilinear section of the outer rail means.

1 2. A rotatable stock container unit substantially as herein described with reference to Figures 1 to 5, or Figures 6 to 9 or Figures 10 to 1 7 of the accompanying drawings.